Fire Resistant Conveyor Belt（DIN-K）

Application Background:

The use of fire-resistant (also called flame-resistant) conveyor belts (Standard:DIN-K/EN12882/JIS-K) in coal mines is conducive to reducing the incidence of both above ground and underground fires. The working environment of coal mines is relatively complicated, coal dust and gas are dangerous factors, and the coal mines being transported are also flammable substances, if electric sparks are generated during transportation, it is easy to cause fires. The use of fire-resistant conveyor belts for coal mines reduces the possibility of electrostatic sparks during coal transportation, and even if static sparks occur, the fire-resistant conveyor belts for coal mines have high flame resistance and maximize the flame spread time.

Currently, there are various flame-retardant conveyor belt standards around the world to ensure the safe use of conveyor belts, such as Germany’s DIN-K, Europe’s EN 12882 (general/above ground) and EN 14973 (underground), ISO 340, the USA’s MSHA 30, Japan’s JIS-K, and Australia’s AS 4606:2012. It is important to note that determining the specific flame-retardant level required for a particular application or environment is crucial. If you are unsure about the required fire resistance level, it is advisable to seek professional advice.

Fire Resistant Capability Test:

JIS/ISO/DIN tests involve exposing six individual samples of a belt to a naked flame, causing them to burn, the source of the flame is then removed and the combustion time (duration of flame) of the test piece is recorded, a current of air is then applied to the test piece for a specified time after the removal of the flame, the flame should not reignite. The time it takes for the belt sample to self-extinguish after the source of ignition (flame) has been removed is then measured. The duration of continued burning (visible flame) should be less than 15 sec. for each sample, with an absolute maximum cumulative duration of 45 sec.

Pulley friction test is the single biggest difference in the safety classifications (standards) between belting used above ground and belting used underground. If certification is required, then these tests must be carried out by an independent test organization. The test standards demand that there should be no evidence of flame or glow during or after the test. This is only achievable by using a PVC belt because the thermoplastic melts/breaks before it reaches 325˚C, the SUNGDA maximum average is around 260 – 270˚C.

Fire resistant conveyor belt carcass type:

Solid woven carcass: This type of carcass woven by Polyester and Nylon filament, dipped through PVC and plasticized, with characteristics of high tensile strength, small elongation, non-peel off, light-body, no delamination, impact resistance, and tear-performance. Mainly applicable to the underground coal mine and other anti-static fireplaces

EP carcass: EP fabric includes polyester toward longitudinal (warp) and polyamide for latitude (weft), with lower longitudinal elongation, full resistance to mildew, moisture and rotting, good flexibility and trough ability. Suitable for middle and long-distance transportation of higher load and speed in the above-ground mining site.

Steel cord carcass: steel cord has super high tensile strength, good trough ability, high adhesion between rubber and steel cord, this type of fire-resistant belt is suitable for large span, long-distance transportation of materials.

When selecting flame-retardant conveyor belts, understanding the customer’s usage environment is crucial. Conveyor belts are used in a variety of settings, from dust-laden factory workshops to explosive environments like mines, as well as in complex outdoor and underground operations. Different scenarios impose different requirements on the flame-retardant properties of conveyor belts. Therefore, scientifically analyzing these environmental conditions, combined with the anti-static and flame-retardant properties of the conveyor belt, ensures safety and efficiency.

Currently, there are three main types of fire-resistant conveyor belts: fabric-layered fire-resistant conveyor belts, steel cord conveyor belts, and solid woven conveyor belts. Among the three types of fire-resistant conveyor belts used in coal mines, the fabric-layered conveyor belt is the most widely used, accounting for over 80% of the market share. It offers stronger flame retardancy while being lighter and more cost-effective.